Re: Slab corruption in 2.6.16-rc5-mm2

[Jesper Juhl <jesper.juhl@gmail.com>]

On Monday 06 March 2006 20:32, Linus Torvalds wrote:
> 
> On Mon, 6 Mar 2006, Jesper Juhl wrote:
> >
> > Not a git user (I need to become one but haven't found the time to read up 
> > on it yet), but no problem, I'll dig out the patch and try reverting it.
> 
> It's attached here.
> 
Thanks.


> NOTE! I'm not at all sure it's the re-try logic. It could be something 
> else. Anything that completes the request before it's actually totally 
> done - or possibly re-uses the sense data for something else would be 
> wrong and buggy.
> 
Ohh well, let's work on the assumption that it is the re-try logic first, 
then try something else if it turns out it isn't. I have no problem testing
a bunch of patches if needed.

<...>
> This is different. But it looks similar. It looks like the thing was 
> actually re-allocated for something else (posix acl data?) but then 

I doubt it's POSIX ACL data : 

juhl@dragon:~/download/kernel/linux-2.6.16-rc5-mm2$ grep -i ACL .config
# CONFIG_FS_POSIX_ACL is not set


> overwritten. However, the overwritten data does look like SCSI sense 
> information again ("Invalid field in cdb"), so I think it's the same 
> thing despite the fact that it had gotten re-allocated for something else.
> 
> > Would gathering more of these help you out?
> 
> It's always interesting when trying to find the pattern, but I think the 
> pattern is already pretty clear. sr_do_ioctl() seems to be the thing, and 
> sense data is written too late.
> 
Ok, it's reproducible on demand (at least I've now reproduced it on 6 more
boots), so if you need any more just let me know and I'll gather a few.


> > I have no USB, SATA or similar devices in the box, only a floppy drive, a 
> > SCSI harddisk, a SCSI CD writer and a SCSI DVD-ROM.
> 
> Well, the fact that you have a CDSI CD-writer and a SCSI DVD-ROM explains 
> the thing, so that's all good.
> 
> > scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 7.0
> >         <Adaptec 29160N Ultra160 SCSI adapter>
> >         aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs
> 
> So it's either an aic7xxx bug, or it's generic SCSI.
> 
> Considering that we've had other slab corruption issues (the reason I was 
> looking closely at yours), generic SCSI isn't out of the question.
> 
> If you were a git user, doing a bisection run would be useful since you 

Well, now is probably as good a time as any for becoming a git user, 
tracking my own patches as individual plain-text files is getting 
un-managable and as you say, bisection would be useful to be able to do.
I'll dig up some git docs and start reading.


> seem to be able to recreate it at will. Oh, well. Testign that one patch 
> would still help.
> 
Hmm, that patch does not apply to the 2.6.16-rc5-mm2 kernel : 

patching file drivers/scsi/scsi_lib.c
Hunk #1 succeeded at 260 (offset 1 line).
Hunk #2 FAILED at 473.
Hunk #3 FAILED at 1394.
2 out of 3 hunks FAILED -- saving rejects to file drivers/scsi/scsi_lib.c.rej
patching file include/linux/blkdev.h
Hunk #1 succeeded at 190 (offset 6 lines).

I'll go see if the problem also exists in mainline - will report on that 
shortly.


 /Jesper